Q 12-08-130JEE MainJEE Main 2022 (26 Jun, Shift 2)Medium
A sinusoidal wave $y(t) = 40\sin(10\times10^6\pi t)$ is amplitude modulated by another sinusoidal wave $x(t) = 20\sin(1000\pi t)$. The amplitude of the minimum frequency component of the modulated signal is
Answer: (D) 10
Modulation index $\mu = \dfrac{20}{40} = 0.5$. The AM wave has the carrier at $f_c$ and side bands at $f_c\pm f_m$, each side band of amplitude $\dfrac{\mu A_c}{2}$.
The minimum frequency component is the lower side band, of amplitude $\dfrac{0.5\times40}{2} = 10$.
Solution by Sreeraj P, M.Sc Physics